Blood component processing system, apparatus, and method

ABSTRACT

A system and method are used in connection with processing of blood components. The processing of blood components may involve centrifugal separation and/or filtering of the blood components. In some examples, at least some blood components are centrifugally separated in a chamber and then filtered via a filter rotating along with a centrifuge rotor, wherein the filter is located closer than the chamber to an axis of rotation of the rotor. The filter may include a porous filtration medium configured to filter leukocytes, platelets, and/or red blood cells. Some examples include a pressure sensor sensing pressure of pumped blood components. The sensed pressure may be used in connection with controlling the pumping of the blood products and/or in connection with determining the location of an interface associated with the blood products. Other uses of the sensed pressure are also possible.

This application is a divisional of U.S. application Ser. No.10/414,475, filed Apr. 16, 2003, now U.S. Pat. No. 7,279,107, whichclaims the benefit of U.S. provisional patent applications: No.60/373,083, filed Apr. 16, 2002, and No. 60/405,667, filed Aug. 23,2002.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a system, apparatus, and method forprocessing components of blood. In particular, some aspects of theinvention relate to processing blood components through the use ofcentrifugal separation, filtration, and/or any other form of processing.

2. Description of the Related Art

Whole blood consists of various liquid components and particlecomponents. The liquid portion of blood is largely made up of plasma,and the particle components include red blood cells (erythrocytes),white blood cells (leukocytes), and platelets (thrombocytes). Whilethese constituents have similar densities, their average densityrelationship, in order of decreasing density, is as follows: red bloodcells, white blood cells, platelets, and plasma. In terms of size, theparticle constituents are related, in order of decreasing size, asfollows: white blood cells, red blood cells, and platelets. Most currentseparation devices rely on density and size differences or surfacechemistry characteristics to separate blood components.

Separation of certain blood components is often required for certaintherapeutic treatments involving infusion of particular blood componentsinto a patient. For example, in a number of treatments involvinginfusion of platelets, there is sometimes a desire to separate out atleast some leukocytes and/or red blood cells before infusing aplatelet-rich blood component collection into a patient.

For these and other reasons, there is a need to adopt approaches toprocessing components of blood.

SUMMARY

In the following description, certain aspects and embodiments of thepresent invention will become evident. It should be understood that theinvention, in its broadest sense, could be practiced without having oneor more features of these aspects and embodiments. It should also beunderstood that these aspects and embodiments are merely exemplary.

One aspect of the invention relates to a system for processing bloodcomponents. The system may comprise a separation chamber including achamber interior in which blood components are centrifugally separatedand an outlet port for passing at least some centrifugally separatedblood components from the chamber interior. A flow path may be in flowcommunication with the outlet port of the separation chamber. Theapparatus may further comprise a filter including a filter inlet in flowcommunication with the flow path, a porous filtration medium configuredto filter at least some of at least one blood component (e.g.,leukocytes, platelets, and/or red blood cells) from centrifugallyseparated blood components passed to the filter via the flow path, and afilter outlet for filtered blood components. The system may furthercomprise a rotor configured to be rotated about an axis of rotation. Therotor may comprise a first portion configured to receive the separationchamber and a second portion configured to receive the filter, whereinthe first and second portions may be positioned with respect to oneanother so that when the separation chamber is received in the firstportion and the filter is received in the second portion, the filter iscloser than the interior of the separation chamber to the axis ofrotation. The system may be configured so that the rotor rotates duringfiltering of at least one blood component via the filter.

In another aspect, the system may be configured so that when the filteris received in the second portion, the filter is eccentric with respectto the axis of rotation. For example, the system may be configured sothat the filter is at least close to the axis of rotation (i.e., closeto the axis of rotation or intersecting the axis of rotation at leastpartially) and so that the axis of rotation does not intersect aninterior flow path defined by the filter. In some examples, when thefilter is received in the second portion, the filter may be offset fromthe axis of rotation so that the axis of rotation does not intersect thefilter. In some examples, the filter is eccentrically positioned so thatblood components exit a housing of the filter (and/or enter the filteritself) at a location that is at least close to the rotor's axis ofrotation, as compared to the location where the blood components enterthe filter housing (and/or where the blood components exit the filteritself).

In a further aspect, the system may be configured so that when thefilter is received in the second portion, a filter housing outflow portis located closer than a filter housing inflow port and/or the porousfiltration medium to the axis of rotation. In another aspect, the filterhousing outflow port may be above the filter housing inflow port.

In an additional aspect, the filter may comprise a filter housingdefining an interior space containing the porous filtration medium,wherein the filter inlet and filter outlet may be in flow communicationwith the interior space, and wherein the system may be configured sothat when the filter is received in the second portion, the filter ispositioned so that blood components flow in the interior space in adirection facing generally toward the axis of rotation. In someexamples, the filter housing defines a filter housing inflow port forpassing blood components to the interior space and a filter housingoutflow port for passing blood components from the interior space. Thesystem may be configured so that when the filter is received in thesecond portion, the filter housing outflow port is closer than thefilter housing inflow port (and/or the porous filtration medium) to theaxis of rotation. In an exemplary arrangement, the filter housingoutflow port is above the filter housing inflow port.

In a further aspect, the second portion may comprise at least one of aledge and a slot configured to receive the filter, the at least one of aledge and a slot being positioned under a top surface of the rotor.Alternatively (or additionally), the rotor may comprise a holderconfigured to hold the filter with respect to the rotor.

There are many possible arrangements for the flow path. In someexamples, the flow path may include tubing. For example, the flow pathmay include a first tubing portion having one end coupled to the outletport of the separation chamber and another end coupled to the filterinlet. In addition, the apparatus may also include a second tubingportion having an end coupled to the filter outlet, wherein the secondtubing portion extends in a direction facing generally away from theaxis of rotation. Further, the system may include a third tubing portiondownstream from the second tubing portion, wherein the third tubingportion extends in a direction facing generally toward the axis ofrotation.

In one more aspect, the rotor may comprise a groove configured toreceive at least some of the tubing (e.g., at least some of the secondand third tubing portions).

One other aspect relates to an apparatus for use with a centrifuge forprocessing blood components. The apparatus could be configured in anumber of different ways. According to one aspect, the apparatus maycomprise the separation chamber, the flow path, and the filter. In someembodiments, the apparatus is configured to be disposed after being usedfor processing of blood components.

In some embodiments, the rotor's axis of rotation may extend through thesecond portion of the rotor.

In another aspect, the system may comprise at least one valving memberon the centrifuge rotor, the valving member being configured to controlflow of at least some of the blood components during rotation of therotor. In some examples, the valving member may comprise a tubing clamp.

In a further aspect, the system may comprise at least one sealing memberon the centrifuge rotor, the sealing member being configured to create aseal during rotation of the rotor. For example, the sealing member maycomprise a tubing welder.

In one further aspect, the rotor may comprise at least one supportmember configured to support the chamber, wherein the at least onesupport member may comprise a guide groove configured to receive aportion of the tubing line and a controllable clamp and/or welderassociated with the groove. For example, the clamp may be configured tocontrollably occlude flow of blood components through the tubing line.In some examples, the chamber may comprise at least one guide holeconfigured to receive the at least one support member.

In some embodiments, the rotor may comprise a plurality of supportmembers located in an asymmetric fashion with respect to the axis ofrotation, and the chamber may comprise a plurality of guide holes, eachof the guide holes being configured to receive a respective one of thesupport members.

According to another aspect, the system may further comprise a pumpconfigured to pump at least some blood components from the chamber. Thesystem may also comprise a pressure sensor configured to sense pressureof the pumped blood components, wherein the system may be configured tocontrol the pump based on at least the pressure sensed by the pressuresensor.

A further aspect relates to a system comprising a chamber (e.g., a bloodseparation chamber) that may comprise an interior configured to containseparated blood components, and an outlet port for passing at least someof the separated blood components from the interior. A flow path may bein flow communication with the outlet port of the chamber. The systemmay further comprise a filter comprising a filter inlet in flowcommunication with the flow path, a porous filtration medium configuredto filter at least some of at least one blood component from separatedblood components passed to the filter via the flow path, and a filteroutlet for filtered blood components. In addition, the system may alsocomprise a pump configured to pump at least some of the separated bloodcomponents from the chamber to the filter via the flow path, and apressure sensor configured to sense pressure of blood components pumpedto the filter. The system may be configured to control the pump based onat least the pressure sensed by the pressure sensor.

In some embodiments, the pump may comprise a portion of a centrifugeand/or at least a portion of a blood component expressor.

According to another aspect, the system may be configured such that thesystem calculates a difference between pressures sensed by the pressuresensor in at least one time interval, determines when the calculateddifference is at least a predetermined amount, and controls the pump inresponse to at least the determination that the calculated difference isat least the predetermined amount.

In yet another aspect, there is a system that may comprises a separationchamber comprising a chamber interior in which blood components arecentrifugally separated, and an outlet port for passing at least some ofthe centrifugally separated blood components from the chamber interior.A flow path may be in flow communication with the outlet port of theseparation chamber. The system also may comprise a pump configured topump at least some of the centrifugally separated blood components fromthe chamber and through the flow path, and a pressure sensor configuredto sense pressure of blood components pumped by the pump. In addition,the system may comprise a centrifuge rotor configured to be rotatedabout an axis of rotation, the rotor comprising a portion configured toreceive the separation chamber. The system may be configured such thatthe system calculates a difference between pressures sensed by thepressure sensor in at least one time interval, determines when thecalculated difference is at least a predetermined amount, and controlsthe pump in response to at least the determination that the calculateddifference is at least the predetermined amount.

Many different types of chambers are possible. In some embodiments, thechamber may have a ring shape.

According to another aspect, the chamber may comprise a bag (e.g., ablood component separation bag). For example, at least a portion of thebag may be formed of at least one of flexible and semi-rigid material sothat the chamber interior has a variable volume. In some embodiments,the bag may have a generally annular ring shape defining a, centralopening.

In another aspect, the chamber interior may include a tapered portionleading to the outlet port.

In a further aspect, the chamber may be configured so that the chamberhas a variable volume, and the pump may be configured to reduce thevolume of the chamber interior. In one example, the pump may beconfigured to apply pressure to the chamber via hydraulic fluid. Such anexample may also include a sensor configured to sense pressure of pumpedblood products, wherein the sensor may be configured to sense pressureof the hydraulic fluid. Certain aspects of the invention could bepracticed with or without a pump and/or pressure sensor, and when suchstructure is present, there are many possible forms of pumping andsensing configurations that could be used.

In an even further aspect, the system may further comprise an opticalsensor, and the system may be configured to control the pump based on atleast one of information sensed by the optical sensor and pressuresensed by the pressure sensor. In one example, an optical sensor may bepositioned to sense blood components in the chamber, and/or an opticalsensor may be positioned to sense blood components at another location,such as a location associated with the flow path (e.g., at a tubing linein flow communication with the filter).

In another aspect, the system may be configured so that the pump pumpsblood components from the chamber during rotation of the centrifugerotor.

In a further aspect, the apparatus may further comprise a collectioncontainer comprising an inlet in flow communication with the filteroutlet and/or the flow path, and/or a portion of the rotor may furthercomprise a cavity configured to receive the collection container andpossibly also the filter. In some examples, there may be more than onecollection container and/or at least one collection container may belocated outside of a centrifugal field during blood componentprocessing.

One more aspect of the invention relates to a method of processing bloodcomponents.

Some exemplary methods may include providing a system disclosed herein.The term “providing” is used in a broad sense, and refers to, but is notlimited to, making available for use, manufacturing, enabling usage,giving, supplying, obtaining, getting a hold of, acquiring, purchasing,selling, distributing, possessing, making ready for use, forming and/orobtaining intermediate product(s), and/or placing in a position readyfor use.

In one more aspect, a method may comprise placing a separation chamberin a first portion of a centrifuge rotor and a filter in a secondportion of the rotor, wherein the filter is located closer than aninterior of the separation chamber to the axis of rotation of the rotor,and wherein the filter comprises a porous filtration medium. The methodmay further comprise rotating the centrifuge rotor, the separationchamber, and the filter about the axis of rotation of the centrifugerotor, wherein the blood components are centrifugally separated in thechamber interior. In addition, the method may comprise removing at leastsome of the centrifugally separated blood components from the separationchamber, and filtering the removed blood components with the filter soas to filter at least some of at least one blood component (e.g.,leukocytes, platelets, and/or red blood cells) from the removed bloodcomponents, wherein at least a portion of the filtering occurs duringsaid rotating.

In another aspect, the method may further comprise pumping at least someof the centrifugally separated blood components from the chamber to thefilter. A further aspect may include sensing pressure of pumped bloodcomponents, and controlling the pumping based on at least the sensedpressure.

In yet another aspect, there is a method comprising pumping at leastsome separated blood components from a chamber (e.g., a blood separationchamber or any other type of chamber structure), filtering the pumpedblood components with a filter so as to filter at least some of at leastone blood component from the pumped blood components, sensing pressureof blood components pumped to the filter, and controlling the pumpingbased on at least the pressure sensed by the pressure sensor. In someexamples, the chamber may be rotated (e.g., via a centrifuge) andseparated blood components may be pumped from the chamber while thechamber is received on a centrifuge rotor and/or after the chamber isremoved from a centrifuge rotor.

A further aspect relates to a method of determining a location of atleast one interface during processing of blood components, wherein themethod comprises pumping at least some centrifugally separated bloodcomponents from a chamber, sensing pressure of the pumped bloodcomponents, and determining a location of at least one interface basedon the sensed pressure, wherein the interface is associated with thepumped blood components. For example, the interface may be, an interfacebetween blood components and air, and/or an interface between differingblood components.

In another aspect, the method may comprise calculating a differencebetween pressures sensed in at least one time interval, determining whenthe calculated difference is at least a predetermined amount, andcontrolling the pumping in response to at least the determination thatthe calculated difference is at least the predetermined amount.

According to another aspect, there is a method of processing bloodcomponents, comprising rotating a chamber about an axis of rotation,wherein blood components are centrifugally separated in the chamber,pumping at least some separated blood components from the chamber,sensing pressure of pumped blood components, calculating a differencebetween pressures sensed in at least one time interval, determining whenthe calculated difference is at least a predetermined amount, andcontrolling the pumping in response to at least the determination thatthe calculated difference is at least the predetermined amount.

In another aspect, the method may further comprise passing bloodcomponents (e.g., filtered blood components) into at least onecollection bag.

In a further aspect, the blood components in the chamber may be bloodcomponents of a buffy coat. Buffy coat blood components are generallyblood components that result from a procedure where platelets andleukocytes along with some amount of red blood cells and plasma havebeen separated from whole blood. Alternatively, any other substancecontaining one or more blood components could be processed.

In some examples, whole blood may be processed in the method. Forexample, whole blood may be introduced into the chamber (e.g., fromone/or more donors, and/or from one or more containers containing blooddonated by one or more donors). In the processing of whole blood, anynumber of blood components may be centrifugally separated, filtered,and/or processed in any other way. For example, components of wholeblood may be separated and pumped into separate, respective containers(optionally while being filtered via one or more filters).

In one more aspect, when blood components are pumped, the pumping maycomprise reducing the volume of an interior of the chamber. For example,the method may comprise applying pressure to the chamber via hydraulicfluid.

In another aspect, the pumping may occur during rotation of a centrifugerotor.

In yet another aspect, the method may comprise optically sensing pumpedblood products, and controlling the pumping based on at least one ofoptically sensed information and sensed pressure. For example, theoptically sensing may comprise optically sensing blood components in thechamber and/or optically sensing blood components in a tubing line(e.g., a tubing line in flow communication with a filter).

In another aspect, the method may further comprise causing at least onevalving member on the centrifuge rotor to control flow of at least someof the blood components during rotation of the rotor. As mentionedabove, the valving member may comprise a tubing clamp.

In a further aspect, the method may further comprise causing at leastone sealing member on the centrifuge rotor to create a seal duringrotation of the rotor. As mentioned above, the sealing member maycomprise a tubing welder.

Aside from the structural and procedural arrangements set forth above,the invention could include a number of other arrangements such as thoseexplained hereinafter. It is to be understood that both the foregoingdescription and the following description are exemplary only.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings are incorporated in and constitute a part ofthis specification. The drawings illustrate exemplary embodiments and,together with the description, serve to explain some principles of theinvention. In the drawings,

FIG. 1 is a schematic cross-section view of an embodiment of a system inaccordance with the present invention;

FIG. 1A is a view similar to that of FIG. 1 showing an alternateembodiment of the system;

FIG. 1B is a top plan view of another alternative embodiment of thesystem;

FIG. 2 is a top plan view of a portion of an apparatus including achamber and filter for use with the systems of FIGS. 1, 1A, and 1B,wherein line I-I of FIG. 2 represents the plane for the cross-sectionviews of the chamber portion shown in FIGS. 1 and 1A;

FIG. 3 is partially schematic view of an embodiment of an apparatusincluding the chamber and filter of FIG. 2;

FIG. 4 is an isometric view of a system including the apparatus of FIG.3;

FIG. 5 is a graph showing pressure plotted over time in connection withan example involving the embodiment of FIG. 1B;

FIG. 6 is a top, partially schematic view of an alternative embodimentof a separation chamber;

FIG. 7 is a schematic view of an example of a controller communicatingwith various possible system components;

FIG. 8 is a schematic, partial cross-section view illustrating theconfiguration of a filter and separation chamber associated with thesystem embodiment of FIG. 1B;

FIG. 8 a is a schematic, partial cross-section view of an alternativefilter configuration;

FIG. 8 b is a schematic, partial cross-section view of anotheralternative filter configuration;

FIG. 9 is a schematic view of a hydraulically operated pump and pressuresensor associated with the system embodiments of FIGS. 1, 1A, and 1B;

FIG. 10 is a schematic view of an alternative embodiment of a systemassociated with a centrifuge;

FIG. 11 is a schematic view of an alternative embodiment of a systemassociated with a blood component expresser;

FIG. 12 is a schematic view of an alternative embodiment of a systemassociated with a blood component expressor; and

FIG. 13 is a schematic view of an embodiment of a system configured toprocess whole blood.

DESCRIPTION OF A FEW EXEMPLARY EMBODIMENTS

Reference will now be made in detail to a few exemplary embodiments ofthe invention. Wherever possible, the same reference numbers are used inthe drawings and the description to refer to the same or like parts.

FIG. 1 shows an embodiment of a system for processing blood components.The system includes a centrifuge 34 in combination with an apparatusincluding a filter 31 and a chamber 4 in the form of a blood componentseparation bag having a ring shape. The centrifuge 34 has a rotor 1including a first rotor portion defining a ring-shaped area 3 receivingthe chamber 4 and a second rotor portion defining a center cavity 2where the filter 31 and possibly also a collection container 33 (e.g., abag used to contain blood components processed by the system) may belocated during a blood component processing operation.

The chamber 4 has an interior 8 in which blood components arecentrifugally separated during rotation of the rotor 34 about an axis ofrotation X. As described in more detail below, at least some of theblood components centrifugally separated in the chamber 4 are passed viaa tubing line 21 to a filter 31 where at least some of at least oneblood component (e.g., leukocytes, platelets, and/or red blood cells) isfiltered before passing the filtered blood component(s) to thecollection container 33.

As described in more detail below, hydraulic fluid in a space 5 locatedbeneath the chamber 4 exposes the chamber 4 to an external pressure thatcauses at least some centrifugally separated blood components to bepumped from the chamber 4. The centrifuge rotor 1 also has an inner lid6 adapted to rotate along with a remainder of the rotor 1 and theseparation chamber 4. The lid 6 is optionally configured to at leastpartially secure the chamber 4, for example, in a clamping fashion alonga line 7 shown in FIG. 2. This may be an effective way to fix theposition of the chamber 4 in the centrifuge rotor 1 and limit thestresses on the inner edge of the bag 1. The centrifuge lid 6 optionallydefines a central opening 53 possibly allowing center cavity 2 to beaccessible externally even when the inner lid 6 is in a closed position.

The centrifuge rotor 1 may include one or more supports 9, 10, 11 shownin FIGS. 1B, 2, and 4 (for example, three to five supports). (The viewof FIG. 1 shows only support 9.) Optionally, the supports extend whollyor partially in the center cavity 2 and thus may define the cavity 2.The above-mentioned clamping of the chamber 4 by the inner lid 6 maylimit, through its greater contact area, the load on the inner edge ofthe chamber 4 and assist in preventing it from slipping over or beingreleased in some other way from supports 8, 9, and 10 during centrifugerotor rotation. As shown in FIGS. 1B and 2, e.g., the respectivesupports 9-11 are optionally somewhat asymmetric (e.g., about therotational axis X), and may thus assist in defining the position of thechamber 4 and its associated tubes in the rotor 1 while holding thechamber 4 in position during centrifuging.

Each of the support members 9-11 may define a respective guide groove,such as groove 12 shown in FIG. 1, which is defined in support 9. Thegroove may be shaped to receive one or more different tubes passingblood components or other fluids in the system. One or more of thesupports 9-11 may be configured so that the guide grooves may beselectively reduced (and/or increased) in size to clamp (and/or unclamp)tubing placed in the grooves, and thereby accomplish valving forregulating the flow of fluids in the apparatus. For example, a portionof the support 9 could be configured to move in a clamping/unclampingfashion in the direction of arrow 13 shown in FIG. 1 so as to functionas a clamp valve for tubing 21 in guide groove 12.

One or more of the supports 9-11 may be configured to weld and/or cuttubes extending in grooves defined in the supports 9-11. For example,electric power to perform welding via supports 9-11 may be passed to thesupports 9-11 via an electrical contact between the rotor 34 and acentrifuge stand. Various different components of the centrifuge mayalso be supplied with power via contact(s). In the embodiment of FIG. 1,the electric power is conveyed via electrical slip ring connectors 14,15 between the rotor and stand portions of the centrifuge, whereinconnector 14 is a rotating part of the centrifuge and connector 15 is asecured part in the centrifuge stand. As shown in FIG. 1, the centrifuge34 may include a centrifuge motor 16 coupled to the rotor 1 so as torotate the rotor 1 about the axis of rotation X. For example, the motor16 may be coupled to the centrifuge rotor 1 by a driving belt 47disposed in operative communication with a motor driving pulley 48 and acentrifuge driving pulley 49. A centrifuge rotation bearing 50 maycooperate with a rotating guide 51.

As shown schematically in FIG. 1, both the collection container 33 andfilter 31 may be received in the center cavity 2. The filter 31 may bedisposed in the cavity 2 in any number of different fashions. In oneexample, shown in FIG. 1, the filter 31 may be arranged in the cavity 2so that components passing through the filter flow in a direction facinggenerally toward the axis of rotation X. In the embodiment of FIG. 1A,the filter 31 is oriented to position a filter inlet 31 a above a filteroutlet 31 b. Due to centrifugal forces generated during rotation of therotor 1, substances flowing through the filter 31 of FIG. 1A may flow ina horizontal direction (as viewed in FIG. 1A) as well as in the verticaldirection.

As shown in FIG. 1A, the filter 31 is optionally disposed in a generallylateral orientation on a small ledge 32 extending into the cavity 2. Acovering member such as inner lid 6 may be configured to contact and/orotherwise cover and hold filter 31 in place. For example, a projection66 extending from the lid 6 and the ledge 32 may define a holder for thefilter 31. Alternatively, the ledge 32 could be moved upwardly from theposition shown in FIG. 1A and/or an inner part of the lid could extendslightly lower. In another alternative arrangement, the filter 31 may bepositioned in the cavity 2 without being restrained, such as in theembodiment shown in FIG. 1.

FIG. 1B shows another embodiment including an alternative placement offilter 31. The filter 31 of FIG. 1B is positioned in a generally lateralorientation with the filter 31 being eccentric with respect to the axisof rotation X. In addition, the filter 31 of the embodiment of FIG. B isoffset slightly from the rotational axis X so that the axis X does notintersect an interior of the filter 31. The filter 31 is positioned sothat substances flowing through the filter 31 flow in a direction 95generally facing toward the axis of rotation X.

FIG. 8 schematically shows an example of how the filter 31 of FIG. 1Bmay be configured. (In FIG. 8, the filter 31 and separation 4 are notdrawn to scale.) As shown in that figure, the filter 31 has a filterinlet 31 a and a filter outlet 31 b at the respective ends of L-shapedtubing segments connected to a filter housing 31 d defining an interiorspace containing a porous filtration medium 31 c. The filter outlet 31 bis located above the filter inlet 31 a; and the filter inlet 31 a islocated closer than both the filter outlet 31 b and filtration medium 31c to the axis of rotation X. The filter housing 31 d defines a filterhousing inflow port 31 e and a filter housing outflow port 31 f abovethe inflow port 31 e. The filter housing outflow port 31 f is closerthan the filter housing inflow port 31 e to the axis of rotation X. Thefilter housing outflow port 31 f is also closer than the filtrationmedium 31 c to the axis of rotation X.

In some examples, such as that of FIG. 8, the relative positioning ofthe filter inlet 31 a, filter outlet 31 b, housing inflow port 31 e,housing outflow port 31 f, and/or medium 31 c, as well as the eccentric(and possibly also offset) positioning of the filter 31, may assist inclearing most (if not all) air from the interior of the filter, ascompared to alternative filtering arrangements which might potentiallycause air to be “locked” therein.

FIG. 8 a shows another example of a filter 31 that could be used in thesystem. As shown in that figure, filter outlet 31 b is located abovefilter inlet 31 a; and filter inlet 31 a is closer than both filteroutlet 31 b and filtration medium 31 c to the axis of rotation X. Inthis example, rather than having the L-shaped tubing segments shown inFIG. 8, filter housing 31 d defines flow passages leading to and fromfilter outlet 31 b and filter inlet 31 a, respectively, such that filterhousing outflow port 31 f is located closer than both filter housinginflow port 31 e and medium 31 c to the axis of rotation x. In addition,outflow port 31 f is above inflow port 31 e.

FIG. 8 b shows a further example of a filter 31 that could be used inthe system. For this example, housing inflow port 31 e and housingoutflow port 31 f are at substantially the same relative positions asfilter inlet 31 a and filter outlet 31 b, respectively. In contrast tothe filter shown in FIG. 8 a, filter housing outflow port 31 f is closerthan both filter housing inflow port 31 e and filtration medium 31 c tothe axis of rotation X. In addition, the inlet 31 a, inflow port 31 e,outflow port 31 f, and outlet 31 b are at substantially the same level.Further, filter outlet 31 b is closer than both filter inlet 31 a andfiltration medium 31 c to the axis of rotation X.

One feature in common with the filter examples of FIGS. 8, 8 a, and 8 bis that blood components flowing in an interior space containingfiltration medium 31 c flow in a direction 95 facing generally towardthe axis of rotation X.

As partially shown in FIG. 1B, the filter 31 may be positioned at leastpartially in a slot 57 offset from the axis of rotation X. The slot 57may be wholly or partially defined in lid 6. Alternatively, the slot 57could be defined using a shelf and projection similar to those shown inFIG. 1A.

Although the embodiments of FIGS. 1, 1A, and 1B show the filterpositioned beneath the top surface of the rotor 34, the filter 31 couldalternatively be arranged partially or completely above the rotor's topsurface. In some alternate embodiments, the filter may even bepositioned at a location that is not within the centrifugal fieldgenerated by rotation of the rotor 1.

In the embodiments of FIGS. 1, 1A, and 1B, the portion of the centrifugerotor defining the ring-shaped area 3 and the portion of the centrifugerotor defining the center cavity 2 are positioned with respect to oneanother so that when the chamber 4 is received in the area 3 and thefilter 31 is received in the cavity 2, the filter 31 is closer than thechamber interior 8 to the axis of rotation X, as schematicallyillustrated in FIG. 8. Such a positioning may avoid the filter 31 frombeing subjected to relatively high centrifugal forces while permittingsubstances being centrifugally separated in the chamber interior 8 to besubjected to such high forces. In some instances, it may be desired forsuch a reduced amount of centrifugal force to be applied to the filter31. For example, in certain filter arrangements, exposure to relativelyhigh centrifugal forces might cause certain potential problemsassociated with bursting of the filter housing, or perhaps negativelyaffect the filtration efficacy. For some filters, such as those thatmight not be significantly impacted by centrifugal forces, alternativepositioning of the filter might be possible.

The filtration medium 31 c shown in FIGS. 1A, 8, 8 a, and 8 b may be anyform of porous medium, such as fibers combined together in a woven orunwoven form, loose fibers, foam, and/or one or more membranes, forexample. The filtration medium 31 c may be configured to filterleukocytes, platelets, and/or red blood cells.

The filter 31 could be configured in any known form. In someembodiments, the filter 31 may be a leukoreduction filter configured tofilter leukocytes from blood components including a concentration ofplatelets. One example of such a filter is the LRP6 leukoreductionfilter marketed by the Pall Corporation of Glen Cove, N.Y. Anotherexample is the Sepacell PLS-10A leukocyte reduction filter marketed byBaxter Healthcare Corp. of Deerfield, Ill. A further example is theIMUGARD filter marketed by Terumo of Japan. It should be understood thatother known leukoreduction filters could also be used and such filtersoptionally may be selected depending upon the process being undertaken.

As shown in FIG. 1B, the inner lid 6 includes one or more grooves 60defined therein for receiving one or more tubing lines. A first tubingportion 21 a places the blood component separation chamber (not shown inFIG. 1B) and filter 31 in flow communication with one another. Tubing 21is flow coupled to the outlet of filter 31. The tubing 21 includes asecond tubing potion 21 b coupled to an outlet of the filter 31 andextending in a direction facing generally away from the rotation axis X.The tubing 21 also includes a third downstream portion 21 c extending ina direction generally facing the axis of rotation X. The groove(s) 60may be configured to receive at least some of the second and thirdtubing portions 21 b and 21 c.

In some embodiments, there may be lids (not shown) other than the lid 6to account for a plurality of processes which may alternatively beperformed by the system. As shown in FIG. 1B, the groove(s) 60 may bearranged to associate the tubing 21 with one or more other features ofthe embodiment. For example, the groove(s) 60 may be arranged to placethe tubing 21 in cooperation/communication with the groove 12 of member9 (and/or with an optical sensor 55 described below), among otherthings.

As shown in FIG. 2, the chamber 4 is optionally in the form of a bagdefined by two sheets of a suitable plastic material (e.g., flexibleand/or semi-rigid plastic material) joined together by circumferentiallywelding radially inner and outer edges 17 and 18. Between the weldededges 17 and 18, there is an open, ring-shaped chamber interior in whichblood components are separated. The chamber 4 includes a central opening(e.g., aperture) 19 which primarily corresponds to the center cavity 2opening. Such a structure may simplify access to the center cavity 2.The chamber 4 shown in FIG. 2 has respective guide holes 109, 110, and111 for receiving supports 9-11, respectively, and thus positioning thechamber 4 with respect to the supports 9-11. The bag materialsurrounding the guide holes 109, 110, and 111 may be welded tostrengthen the material around the holes. The guide holes 109, 110, and111 optionally have an asymmetric arrangement (about rotational axis X)that is like that of the optional asymmetric orientation of the supports9, 10, and 11 so as to facilitate orienting the chamber 4.

At least a portion of the chamber 4 may be formed of flexible and/orsemi-rigid material so that the interior of the chamber 4 has a variableinner volume. For example, the chamber 4 may be formed of materialpermitting external pressure to be applied to the chamber so as toreduce the inner volume of the chamber 4. In some exemplaryarrangements, the chamber 4 and possibly the other parts of theapparatus 100 may be formed of material comprising inert plastic.

The chamber 4 includes an inlet port 4 a for passing blood components tothe interior of the chamber 4 and an outlet port 4 b for passing atleast some centrifugally separated blood components from the chamberinterior. Inflow tubing 20 and outflow tubing 21 are placed in flowcommunication with the ports 4 a and 4 b, respectively, on oppositefacing sides of the chamber 4 via welded sleeve couplings 24. Eachsleeve coupling 24 may be a securing part in the form of a short pieceof tubing with a diagonally arranged flat securing collar which may bewelded to the chamber 4, while permitting the respective tubing 20 and21 to be welded to the coupling 24. Instead of being secured via such asleeve coupling, the tubing could alternatively be secured to (and/orin) each respective welded edge, i.e. within welded edges 17 and 18.

An alternative embodiment of a chamber 4 is shown in FIG. 6, wherein, asort of bay 75 is positioned at the outlet port leading to tube 21. Thisbay 75 is defined by a gradually tapered portion formed by weld portions61 and 62 extending in a generally radial direction from the outletport. (The chamber 4 shown in FIG. 2 may have a similar bay.) This typeof arrangement may enable platelets to be received in a relativelynon-abrupt or otherwise non-disruptive process. This may enhance thequality of the harvested platelets.

Referring again to FIG. 6, an inlet area 65 in the region of an inletport leading from tube 20 does not have a tapered portion defined byweld portions 63, 64. This configuration may alleviate any potentialcapture of platelets (or some other desired product) so as to permitplatelets to be available for harvesting at the outlet area 75.

When the chamber 4 is formed in a ring shape, as shown in the drawings,the chamber 4 and at least certain aspects of the centrifuge 34 may beconfigured like the separation chambers and associated centrifugesdisclosed in one or more of the following patent documents: WO 87/06857,U.S. Pat. No. 5,114,396, U.S. Pat. No. 5,723,050, WO 97/30715, and WO98/35757, for example. Many alternative arrangements are also possible.

Although the embodiments shown in the drawings include a separationchamber in the form of a ring-shaped bag, it should be understood thatthere are many alternative forms of separation chamber configurationsthat could be used. For example, the separation chamber could be in theform of a bag other than a ring-shaped bag. Alternatively, theseparation chamber could be in other non-bag forms, such as, forexample, in the form of one of the separation vessels disclosed in U.S.Pat. No. 6,334,842.

In one alternative embodiment (not shown), a filter similar to (oridentical to) filter 31 could be positioned in tubing 20 to filter atleast some blood components (e.g., leukocytes, platelets, and/or redblood ceils) from substances being passing into the chamber 4.

FIG. 3 shows an embodiment of an apparatus 100 including the chamber 4and filter 31 shown in FIG. 2. This exemplary apparatus 100 is in theform of a bag set for producing platelets from a buffy coat collection.The apparatus 100 further includes a bag 23 containing dilutingsolution, a solution tube 30, four connecting tubes 25-28 intended to becoupled (e.g., via welding) to respective bags containing previouslyprepared buffy coat products (not shown), and a multi-way connector 29connecting the tubes 25-28 and 30 to the inflow tubing 20 coupled to theinlet port of chamber 4. From the chamber 4, the tubing 21 having filter31 in-line is coupled to an inlet 33 a of collection container 33, whichis in the form of a bag. In an area where the solution tube 30 iscoupled to the solution bag 23, there may be a blocking switch 45 (e.g.,frangible member) capable of being placed in an open, flow-permittingposition by bending the tube 30 and breaking open the connection so asto initiate the addition of diluting solution to bags (not shown in FIG.3) connected to tubing lines 25-28. Before the blocking switch 45 isopened, solution tube 30 may be arranged in a guide groove 12 defined byone of the supports 9-11 so as to provide a clamp valve intended forcontrolling the addition of diluting fluid to buffy coat bags associatedwith lines 25-28

Although four connecting tubes 25-28 are shown in FIG. 3, any number oftubes may be used. For example, the number of connecting tubes may bebetween four and six or between four and eight.

The system embodiments of FIGS. 1, 1A, and 1B include a pump configuredto pump at least some centrifugally separated blood components from thechamber 4 to the filter 31, and those embodiments also include apressure sensor configured to sense pressure of the pumped bloodcomponents. As shown schematically in FIG. 9, a pump 80 may include ahydraulic fluid flow passage 88 passing through centrifuge rotor 1. Oneend of the hydraulic fluid flow passage 88 is in flow communication witha portion of ring-shaped area 3 positioned beneath the chamber 4 andseparated from the chamber 4 via a flexible membrane 22. Another end ofthe hydraulic fluid flow passage 88 is in flow communication with ahydraulic fluid pressurizer 84 including a piston movable in a hydraulicfluid cylinder via a driver motor 82 (e.g., a stepper motor that moves alead screw). Optionally, a hydraulic fluid reservoir 86 and associatedhydraulic fluid valve 90 may be used to introduce and/or removehydraulic fluid to/from the hydraulic fluid flow passage 88.

In response to a control signal from a controller 68, the driver motor82 drives the piston of pressurizer 84 so as to pressurize ordepressurize hydraulic fluid in the flow passage 88 (e.g., depending onthe direction of travel of the pressurizer piston). The pressurizationof the hydraulic fluid causes pressure to be applied to the chamber 4via the hydraulic fluid pressing against membrane 22. The pressureapplied to the chamber 4 causes the interior volume of the chamber 4 tobecome reduced and thereby pump centrifugally separated blood componentsfrom the chamber 4. Increasing the pressure of the hydraulic fluidcauses an increase in the flow rate of the blood components pumped fromthe chamber 4. Conversely, a decrease of the hydraulic fluid pressurecauses a decrease (or halting) of the pumped flow of blood componentsfrom the chamber 4.

The pressure of the hydraulic fluid is related to the pressure of bloodcomponents being pumped from the chamber 4. As shown in FIG. 9, apressure sensor 70 is configured to monitor the pressure of thehydraulic fluid in the hydraulic fluid flow passage 88. Due to therelationship between the pressure of the hydraulic fluid and thepressure of the pumped blood components, the hydraulic fluid pressuresensed by the pressure sensor 70 reflects the pressure of the bloodcomponents pumped from the chamber 4. In other words, the pressuresensed by the pressure sensor 70 of FIG. 9 is essentially the same as(or at least proportional to) the pressure of the pumped bloodcomponents.

The hydraulic fluid may be any suitable substance. For example, thehydraulic fluid may be a fluid having a density slightly greater thanthat of packed red blood cells. One example of such a substance isGlycol. The hydraulic fluid may alternatively comprise oil.

A number of different pumping and/or blood component pressure sensingarrangements other than those shown in FIG. 9 are possible. For example,the amount of current needed to drive the driver motor 82 associatedwith the hydraulic fluid pressurizer 84 may indicate the pressure ofboth the hydraulic fluid and the blood components. In other examples,the pressure of the blood components could be sensed more directly(e.g., not via hydraulic fluid) using any type of pressure sensor.

The pump 80 may be controlled based at least partially on the pressuresensed by the pressure sensor 70. In the embodiment of FIG. 9, thecontroller 68 could be configured to control the driver motor 82 basedat least partially on the pressure sensed by the pressure sensor 70. Forexample, the controller 68 could be configured such that the controller68 calculates a difference between pressures sensed by the pressuresensor 70 in at least one time interval while blood components arepumped by the pump 80, determines when the calculated difference is atleast a predetermined amount, and controls the pump 80 in response to atleast the determination that the calculated difference is at least thepredetermined amount. Such an arrangement could enable a feedbackcontrol of the pump 80, for example, when the pump is initially operatedvia a volume flow rate command.

As explained in more detail below, in a procedure attempting to collecta maximum number of platelets and a minimum number of white and redblood cells, the control of the pump 80 based at least partially on thesensed pressure may be used to stop the pumping of the blood componentsfrom the chamber 4 in response to an increased pressure reflecting thatrelatively viscous red blood cells are entering the filter 31 andcausing an occlusion of flow through the filter 31.

The pressure sensed by the pressure sensor 70 could enable adetermination of the location of one or more interfaces associated withseparated blood components being pumped from the chamber 4. For example,the pressure sensed by the pressure sensor 70 could indicate thelocation of an interface between blood components and air present in thesystem at the start-up of a blood component processing procedure. Insuch an example, an increase in pressure might reflect that an air-bloodcomponent interface is near (or at) a radially outward portion of afluid flow path (e.g., in FIG. 1B, the location F₀). In another example,the pressure could provide an indication of the location of an interfacebetween blood components having differing viscosities. For example, anincrease of the pressure sensed by the pressure sensor 80 during thefiltering of at least some blood components via the filter 31 couldprovide an indication that a blood component interface (e.g., between afirst phase including primarily liquid (i.e., plasma and possibly one ormore liquid additives) and platelets, and a second phase includingprimarily red blood cells and white blood cells) is located near (or at)the filter 31, and/or a particular location in the flow path leading toor from the filter 31, and/or a particular location in the chamber 4.

The pressure sensed by the pressure sensor 70 could reflect a“fingerprint” of the operation of the system. For example, the sensedpressure could reflect one or more of, the following: a kinking of fluidflow lines; a leak (e.g., rupture) of the membrane 22, chamber 4, and/orflow path leading to and from the filter; an increased likelihood ofplatelet activation (e.g., a high pressure might reflect forcing ofplatelets through the filter 31); a defect and/or clogging associatedwith the filter 31; and/or a possible need for maintenance (e.g., anindication that the membrane 22 is worn).

The pressure sensed by the pressure sensor 70 could also be used tooptimize (e.g., reduce) the time for processing (e.g., separation) ofblood components. For example, when the pressure sensed by the pressuresensor 70 indicates a location of particular blood components, the pump80 could be controlled to use differing flow rates for differing bloodcomponents (e.g., use a faster flow rate for pumping certain bloodcomponents, such as plasma).

In addition to pressure sensor 70, embodiments of the system may alsoinclude one or more optical sensors for optically sensing bloodcomponents, and the pumping of the blood components may also becontrolled based on at least information sensed by the opticalsensor(s). As shown schematically in FIGS. 1 and 1A, a first opticalsensor 52 is positioned in the centrifuge rotor 1 adjacent the chamber 4to optically sense blood components in the chamber 4. (Although notshown in FIG. 1B, the embodiment of FIG. 1B also includes such asensor.) In addition, as shown in FIG. 1B, the system also may include asecond optical sensor 55 positioned to optically sense blood componentsflowing through the tubing line 21 at the second tubing portion 21 b,located downstream from the filter 31.

The optical sensors could be configured in the form of any type ofoptical sensor used in association with blood components. One example ofan optical sensor may include a photocell. The first and second opticalsensors 52 and 55 may be configured to detect a change of color of bloodcomponents. Such a change of color may be indicative of the location ofan interface between differing blood component phases, such as aninterface where one of the phases that defines the interface includesred blood cells.

The first optical sensor 52 may be located at a particular radialposition on the centrifuge rotor 1 so as to sense when an interface hasmoved to that location in the chamber 4. For example, the pumping ofblood components from the chamber 4 could be slowed 9 (e.g., via areduction of hydraulic pressure with the arrangement of FIG. 9) inresponse to the first optical sensor 52 detecting an interface (e.g., aninterface partially defined by red blood cells) approaching a radiallyinward location. Similarly, the second optical sensor 55 may detect thepresence of an interface (e.g., an interface partially defined by redblood cells) along the flow path leading from the chamber 4. In someexamples, the controller 68 could be configured so as to halt pumping ofblood components from the chamber 4 in response to the second sensor 55sensing an interface (e.g., an interface partially defined by red bloodcells) and/or in response to a determination that the difference betweenpressures sensed by the pressure sensor 70 is at least a predeterminedamount.

FIG. 7 shows a schematic view of an example of the controller 68 thatmay be used to at least partially control certain features of thesystem. The controller 68 communicates with various system components.For example, the controller 68 could communicate with the pump 80,centrifuge motor 16, pressure sensor 70, first optical sensor 52, secondoptical sensor 55, valving structure 72 (e.g., the valves defined bysupports 9, 10, 11), and a control panel 36. The controller 68 may beconfigured to cause rotation of the centrifuge rotor 1 during filteringof at least some blood components (e.g., leukocytes, platelets, and/orred blood cells) via the filter 31 received in the cavity 2. In someembodiments, this may enable centrifugal separation in the chamber 4 andfiltering via the filter 31 to occur at least partially simultaneouslyin a somewhat on-line fashion, as compared to some other approacheswhere filtering takes place a period of time after initial centrifugalseparation and removal of a separation chamber and possibly also afilter from a centrifuge rotor. Alternatively (or additionally), thecontroller 68 may be configured so that filtering via the filter 31takes place at least some time after at least an initial separation ofblood components in the chamber 4.

The controller 68 may control the rotational speed of the rotor 1. Inaddition, the controller 68 may control the pump 80 and/or valvingstructure 72 to control the pumping of substances flowing to and fromthe chamber 4 and the filter 31. The controller 68 may include aprocessor having programmed instructions provided by a ROM and/or RAM,as is commonly known in the art. Although a single controller 68 havingmultiple operations is schematically depicted in the embodiment shown inFIG. 7, the controlling may be accomplished by any number of individualcontrollers, each for performing a single function or a number offunctions.

The controller 68 may be configured to pump hydraulic fluid at aspecified flow rate. This flow rate may cause a blood component flowrate with a resultant pressure. The controller 68 may then take readingsfrom the pressure sensor 70 and change the flow rate based on thosereading so to control flow rate as a function of pressure measured.

A number of different pumping and/or blood component pressure sensingarrangements other than those shown in FIG. 9 are possible. In addition,there are a number of alternative ways in which the pumping of bloodcomponents from the chamber 4 could be controlled.

FIG. 10 schematically illustrates an embodiment where blood componentsare pumped from chamber 4 via a pump 80 positioned downstream from thefilter 31 at a location outside of the centrifugal field generated byrotation of centrifuge rotor 1. Such a pump 80 could be configured inthe form of a peristaltic pump or any other type of pump suitable forpumping blood components.

As shown schematically in FIG. 10, the pressure sensor 70 could directlysense the pressure of pumped blood components (rather than via hydraulicfluid) from a location on the centrifuge rotor 1. Alternatively (oradditionally) the pressure of the blood components could be senseddirectly by a pressure sensor 70′ located outside of the centrifugalfield caused by rotation of the rotor 1. Similarly, a filter 31′ inplace of (or in addition to) filter 31 could be located at a locationoutside of the centrifugal field of the rotor 1. Additionally, thecollection container 33 may be located outside of the centrifugal field.In a further modification, the system might be modified so that there isno filter.

In other embodiments, at least some structural features might not bepart of a centrifuge structure. For example, FIG. 11 schematically showsan embodiment in the form a blood component expressor including a pump80 configured to pump blood components from a chamber 4. The pump 80 ofFIG. 11 includes a pair of clamping plates 92 and 94 that apply pressureto chamber 4 when a clamp driver 96 moves the clamping plates 92 and 94together. A controller 68 controls the pump 80 based at least partiallyon pressure of pumped blood products sensed directly via the sensor 70.The chamber 4 could be a chamber that has been removed from a centrifugerotor after blood components in the chamber 4 have been previouslystratified in a centrifuging procedure.

FIG. 12 schematically shows an embodiment similar to that of FIG. 11,but substituting a pump 80 like that shown in FIG. 10.

The following provides a discussion of an exemplary blood processingmethod that could be practiced using the system embodiments shown inFIGS. 1, 1A, 1B, 2-4, and 6-9. Although the exemplary method isdiscussed in connection with the structure shown in those figures, itshould be understood that the exemplary method could be practiced usingalternative structure. (In addition, the structure shown in thosefigures could be used in alternative methods.)

FIG. 4 shows certain components of the apparatus shown in FIG. 3, butsome of those components are drawn to a smaller scale or are not visiblein FIG. 4. As shown in FIG. 4, centrifuge 34 is shown standing with itsouter lid 35 completely open and locked in that position. The centrifugeinner lid 6 (see FIGS. 1 and 1A) has been omitted to show other partsmore clearly. Also, the centrifuge rotor 1 and chamber 4 have, to acertain extent, been drawn in a simplified manner. The centrifugecontrol panel 36 is also shown schematically.

FIG. 4 illustrates four blood bags 37-40 containing buffy coat suspendedin a cassette 41, which is mounted on the inside of the centrifuge outerlid 35. Buffy coat bags 37-40 have individual output lines connected bysterile welding to tube connectors 25-28 (see FIG. 3). The fluid contentof the bags is introduced into the chamber 4 via the tubes 25-28 andconnecting tube 20. After (or before) that, the buffy coat bags 37-40may be supplied with washing fluid and/or diluting solution fromdiluting solution bag 23 suspended from a holder 44. The dilutingsolution contained in the bag 23 may be plasma or any other standarddiluting solution. An example of a conventional diluting solution is aPAS (platelet additive solution), such as, e.g., T-Sol. Dilutingsolution bag 23 is suspended sufficiently high above bags 37-40 to allowthe diluting solution to be added in sufficient amounts to these bags assoon as blocking switch 45 in tube 30 and a clamp valve in support 11,through which tube 30 is passed, are opened. Communication between bags37-40 and chamber 4 proceeds via tube 20 which in turn passes through aclamp valve in support 10, for example, for controlling fluidcommunication. After the addition of diluting solution in sufficientamounts to bags 37-40, a motor (not shown) connected with the cassette41 may be started and operated to move the cassette 41 back and forth ina curved pendulum movement 42 (or alternatively a complete (orsubstantially complete) rotational movement) until all the concentratesubstance in the buffy coat bags 37-40 is resuspended.

Various arrangements may cause the agitation movement of the cassette41. For example, the motor driving the cassette movement may beassociated with a gear box, or there may be a crank function or controlof the motor. It may also be theoretically possible to use a hydraulicmotor, but it might have a slower shaking speed and longer mixing time.

Then, the built-in clamp valve in the support member 10 may be opened soas to cause flow of substantially all of the substance from the bags37-40 to the chamber 4 via the tubing 20. The tube 20 in support 10 maythen be sealed by sterile welding provided by the support 10 so as toblock fluid communication through the tube 20, and thereafter (orsubstantially simultaneously therewith) the support 10 may cut the tube20, so that the empty bags 37-40 and bag 23 with any possible solutionand/or concentrates from the buffy coat diluting solution mixture may bedisposed. If desired, the flushing out of the buffy coat bags 37-40could be carried out in one, two, or several consecutive flushingoperations. After flushing out the buffy coat bags, cassette 41 andholder 44 may then be removed from the centrifuge lid 35 and thereafterthe centrifuge lid 35 may then be closed and a centrifuging operationmay be carried out.

Before centrifuging, the chamber 4 is placed in the ring-shaped area 3(see FIGS. 1 and 1A) and the collection container 33 (see FIGS. 1, 1Aand 3) and filter 31 are placed in the center cavity 2 (see FIGS. 1, 1A,and 1B). During centrifuging, the centrifuge rotor 1 is rotated aboutthe axis of rotation X, thereby causing the blood platelet product to beseparated from the other buffy coat components (e.g., red and whiteblood cells) in the chamber 4. Then, after (or in some embodiments,during) that separation, at least some of the platelet product may bepumped to the collection container 33 by increasing the pressure ofhydraulic fluid passed into the ring-shaped area 3 under the membrane 22shown in FIG. 9, and thereby applying external pressure to the chamber 4that causes a reduction of the volume of an interior of the chamber 4.As is understood in the art, such a pressure applied by hydraulic fluidmay occur during continued centrifugation (continued rotor spinning). Itotherwise may be applied before rotor rotation has begun or even afterrotation has halted.

The pumped blood components are removed from the chamber 4, optionallyfiltered by the filter 31, and then conveyed to collection container 33.As shown in FIG. 1B, arrows F show flow through portions of the filter31 and the tubing line 21 (which passes through the second sensor 55 andsupport member 9) and thence into collection container 33. The flow pathof material out of chamber 4 begins through first tubing portion 21 aupstream from filter 31. Flow through tubing portion 21 a emanates firstfrom chamber 4, then travels through or near the axis of rotation Xwhere the centrifugal forces are the lowest (zero or very near thereto)of any point in the system. The application of hydraulic pressure(and/or the centrifugal force) continues to then push the flow into thefilter 31. As shown in FIGS. 1B and 8, the blood components may flow inan interior space of the filter housing 31 d in a direction 95 facinggenerally toward the axis of rotation X. After exiting the filterhousing, the blood components flow in a direction generally facing awayfrom the axis of rotation X, through the second tubing line portion 21b, radially outwardly and through the second optical sensor 55. Then,the flow reaches its radially outermost point of travel, here indicatedas point F₀, relative to the axis of rotation X. Flow then proceedsroughly inward via third tubing portion 21 c, while passing through thesupport member 9, and the valving and/or sealing mechanism therein. Theflow then proceeds to the container 33 disposed in the central cavity 2.

The filter 31 (e.g., a leukoreduction filter) may be configured tofilter at least some undesired components. For example, where thedesired product is platelets, the filter 31 may filter leukocytes and/orred blood cells. The filtration may occur substantially simultaneouslywith the removal (e.g., pumping) of components from the chamber 4, andalso may be performed at least partially during rotation of thecentrifuge rotor 1.

The exemplary method further includes optical sensing of bloodcomponents via the first and second optical sensors 52 and 55. In theexemplary method, the flow rate at which blood components are pumpedfrom the chamber 4 may be reduced when the first optical sensor 52senses that an interface (e.g., an interface between desired lightersubstance (e.g., platelets) and a darker non-desired concentrate product(e.g., red blood cells and/or leukocytes)) is approaching a radiallyinward location (e.g., a location at or near the tubing 21). Forexample, such a reduction of the flow rate might be achieved by reducingthe hydraulic pressure applied to the membrane 22 shown in FIG. 9.

The pumping of blood components from the chamber 4 may be interrupted orhalted when the second optical sensor 55 senses an interface (e.g., aninterface defined at least partially by red blood cells).

The exemplary method also includes sensing the pressure of bloodcomponents pumped from the chamber 4. In the embodiment shown in FIG. 9,the pressure of the pumped blood components is sensed via sensing of thepressure of the hydraulic fluid used to pump the blood components fromthe chamber 4.

FIG. 5 illustrates an exemplary graph showing pressure sensed by thepressure sensor 70 of FIG. 9 relative to time during the processing ofblood components in the exemplary method. Prior to a time T₀, there isrelatively little (or no) sensed pressure because there is some initialtime that may be dedicated to mere centrifugation/rotation of thecentrifuge rotor 1 to effect the separation of the blood components intostratified layers before much hydraulic pressure is added to pump theblood products (in some alternative examples, pressure may be addedsooner (or later) and perhaps even from the beginning of the rotation).At time T₀, the pressure of the hydraulic fluid is increased to beginpumping of blood components from the chamber 4. In some examples, thecontroller 68 could provide a relatively constant volume flow rate ofhydraulic fluid, and, as described below, the hydraulic fluid flow couldbe altered based on sensed pressure feedback.

The initial pumping of blood components from the chamber 4 pushes aninterface defined by the blood components and air initially present inthe system at the beginning of the centrifugation. An increased amountof hydraulic pressure (and corresponding increase in pressure of thepumped blood components) occurs up until there is a peak of pressure P₁at a time T₁. The pressure peak at time T₁ provides an indication thatthe air-blood component interface (e.g., interface between air andplatelet rich plasma) has reached a particular location in the flow pathdefined by the system. For example, the pressure peak at time T₁ mayrepresent that the air-blood component interface is located in thefilter 31. Alternatively, the pressure peak at time T₁ may represent aform of “siphon” effect associated with pumping the air-blood componentinterface to the radially outermost flow path point F₀ shown in FIG. 1B.After reaching the point F₀, substances may encounter a bit ofresistance due to centrifugal forces (which also contribute to keepingheavier phase materials at further radii from the axis of rotation)encountered when flowing back inwardly toward a lesser radius (whichdescribes all points in the flow other than point F₀). Thus, a sort ofback pressure may be built up.

After the air-blood component interface has been pumped past thelocation identified by the pressure peak at time T₁, the pressurereaches a reduced pressure level P₂ at time T₂. In a time period from T₂to T₃, the pressure remains substantially constant at level P₂ whileblood components (e.g., plasma, possible additive solution(s), andplatelets) are pumped from the chamber 4, through the filter 31, andinto the collection container 33. In the example represented by thegraph of FIG. 5, the controller 68 has reduced the hydraulic pressurelevel to P₃ at time T₃ in response to the first optical sensor 52sensing an interface defined at least partially by red blood cells inthe chamber 4. The reduction of the hydraulic pressure causes acorresponding reduction of the pressure of the pumped blood componentsas well as a reduction of the flow rate of the pumped blood components(as compared to that in the time interval from T₂ to T₃). The reductionof the flow rate of the pumped blood components may reduce thelikelihood that a substantial number of red and white blood cells willpass into the collection container 33. Additional flow rate reductionsmay also be possible for alternative examples.

The sensed pressure remains relatively constant at pressure P₃immediately after time T3 and then the sensed pressure increasessomewhat rapidly. The increased pressure represents that an interfacedefined between a phase of relatively low viscosity blood components(e.g., primarily liquid (i.e., plasma and possible liquid additive(s))and platelets) and a phase of relatively high viscosity blood components(e.g., primarily red blood cells and white blood cells) is beginning toenter the filter 31. The relatively high viscosity blood cells (e.g.,red blood cells) are unable to pass through the filter 31 as easily asliquids and other relatively low-viscosity components. As the relativelyviscous blood components continue to enter the filter 31, they become“packed” in the filter 31 and cause an increasing back pressure sensedby the pressure sensor 70.

The controller 68 receives signals indicative of the pressure sensed bythe pressure sensor 70. In the exemplary time interval from T₃ to T₄,the controller 70 calculates the difference between maximum and minimumpressures sensed by the pressure sensor 70, and the controller 70determines when that calculated difference exceeds a predeterminedamount. Then, in response to such a determination, the controller 70controls the system so as to cause a significant reduction of hydraulicpressure and corresponding halting or ending of the pumping of bloodcomponents from the chamber 4 (e.g., the piston of pressurizer 84 couldbe retracted and/or valve 90 shown in FIG. 9 could be opened).

In the example shown in FIG. 5, at time T₄, the pressure reaches a peakat P₄ sufficient to cause a pressure difference ΔP (the differencebetween P₄ and P₃) indicating that the location of the interface definedby the viscous blood components has been pumped to (and possiblyslightly beyond) the filter 31. In response to that pressure differenceΔP being determined by the controller 68, the controller 68 discontinuesthe pumping of blood components from the chamber 4 so that an excessivenumber of the viscous blood components will not be passed to thecollection container 33. Accordingly, the pressure after T₄ reflectsthat hydraulic pressure is no longer applied to the chamber 4.

In some alternative examples, the system may be configured so that inresponse to a sufficient pressure difference, the pressure of thehydraulic flow may be altered (increased or decreased) to continuepumping of blood components at a different flow rate. This could happenmultiple times during a single processing procedure.

For the example shown in FIG. 5, the pressure difference ΔP may be about0.2 bar. Many other differentials could be used depending on a number offactors.

The generally flat portions of the pressure diagram (e.g., between T₂and T₃ or between T₃ and T₄) indicate that there are no significantdiscrete phases of blood components passing from the chamber 4. Thoseflat portions might be interpreted as an indication of a desired flowrate. Such a flow rate may be determined in advance of a bloodprocessing procedure and used as a form of feedback control so that whenthe desired flow rate is reached (as measurable by a discrete sensor(not shown)), the pressure may be leveled as shown and maintained,before encountering a pressure difference indicating a possiblecondition where it might be desire to cease (or otherwise alter)hydraulic pressure.

In some instances, the actual level of relatively steady pressuresensing (e.g., e.g., between T₂ and T₃ or between T₃ and T₄) might notbe the same or even nearly the same value from one run to another. Thus,the interpretation of the pressure difference may not be determined byany particular pressure point, but rather may be expressed as and/or bedependent upon a certain minimum change in pressure regardless of thestarting or ending pressure level.

The sensing of the pressure to determine the location of interfacesbetween phases could be used even in some blood component processingprocedures that do not include centrifugation separation and/orfiltration. For example, in a procedure that includes centrifugation,but not filtration, the sensing of pressure might be used to determinewhen an interface reaches a radially outermost position (similar to theposition F₀ shown in FIG. 1B.

After an identification of the location of a blood component interfacevia the pressure sensing and/or the optical sensing (e.g., whicheverdetects the interface first), there could be a time delay before thepumping of blood components from the chamber 4 is discontinued. Forexample, in a procedure where platelets are being collected, at least aslight time delay might maximize a platelet collection while presentinga relatively low risk of causing a significant number of red and whiteblood cells to be collected along with the platelets.

When the pumping of blood components has been discontinued, the tubing21 may be clamped shut (via the optional clamp associated with one ormore of supports 9-11) and possibly also sealed and cut via sterilewelding supplied by one or more of the supports 9-11 (e.g., support 9).Thereafter, the chamber 4 containing non-desired concentrates ofparticular blood components (e.g., red blood cells, etc.), may beremoved from the centrifuge and disposed.

Systems and methods in accordance with the invention may be used in theprocessing of whole blood. For example, FIG. 13 schematicallyillustrates an embodiment of a system configured to process whole blood.As shown in that figure, whole blood from a whole blood source 100(e.g., one/or more donors, and/or one or more containers containingblood donated by one or more donors) may be introduced into a chamber4′, which may be configured at least similar to the chamber 4 discussedabove. For example, the chamber 4′ may include a variable volumeinterior that may be reduced via hydraulic pressure so as to pumpcentrifugally separated blood components from the chamber 4′. Asdiscussed in some of the above examples, alternative pumps may also beused. The pumping may optionally be controlled based on pressure sensingand/or optical sensing in a manner at least similar to that discussedabove in connection with FIGS. 1, 1A, 1B, 5, 7, and 9-12.

The chamber 4′ may include a single outlet or more than one outlet. Inthe example shown in FIG. 13, separate outlets may be associated withremoval of particular blood components from the chamber 4′. In addition,a plurality of collection containers 33′, 33″, and 33′″ may berespectively flow coupled to those outlets so as to collect separateblood components separated in the chamber 4′. For example, thecollection container 33′ may be used to collect a platelet product,collection container 33″ may be used to collect a plasma product, andcollection container 33′″ may be used to collect a red blood cellproduct. One or more of the containers 33′, 33″, and 33′″ may be eitherreceived in centrifuge rotor 1 or positioned at a location outside ofthe centrifugal field.

One or more of filters 31′, 31″, and 31′″ may be associated with each ofthe respective flow paths leading from the chamber 4′ to the containers33′, 33″, and 33′″. The filters 31′, 31″, and 31′″ may be configured atleast similar to filter 31 discussed above. One or more of the filters31′, 31″. and 31′″ may either be received in a portion of the centrifugerotor 1 or located outside of the centrifugal field. Although FIG. 13shows a separate, respective filter 31′, 31″, 31′″ associated with eachof the flow paths leading from the chamber 4′, many other arrangementsare possible. For example, one or more of the filters 31′, 31″, and/or31′″ (e.g., filter 31″) may be omitted, and/or the filter outlets may becoupled to more than one collection container, and/or a single filtermay be used for multiple flow paths.

In the embodiment of FIG. 13, one or more controllable clamps associatedwith one or more the supports 9, 10, 11 may be used to control flow ofsubstances to and/or from the chamber 4′. One or more welders associatedwith one or more of the supports 9, 10, and 11 may be used to sealtubing lines leading to the containers 33′, 33″, and 33′″. For example,such clamps and welders may be operated during rotation of the rotor 1.

In some alternative embodiments, other optional components, accessoriesand/or methods may be used in addition or in lieu of certain featuresdescribed hereinabove. An example is a leukoreduction system, involvingan LRS® chamber described in numerous publications including variousU.S. and foreign patents (e.g., U.S. Pat. No. 5,674,173, among others).Other potential accessory devices may include sampling devices ofnumerous types including, for example, bacteria screening devicesreferred to as Bact-T Alert® devices.

In addition, an adapted database associated with a barcode reader may beutilized to make all the blood products processed by the system directlytraceable and that database may also contain all control criteria forfeasible blood product processing stages of the system.

It will be apparent to those skilled in the art that variousmodifications and variations can be made to the structure andmethodology described herein. Thus, it should be understood that theinvention is not limited to the subject matter discussed in thespecification. Rather, the present invention is intended to covermodifications and variations.

1. A system for processing blood components, comprising: a chambercomprising an interior configured to contain separated blood components,and an outlet port for passing at least some of the separated bloodcomponents from the interior; a flow path in flow communication with theoutlet port of the chamber; a filter comprising a filter inlet in flowcommunication with the flow path, a porous filtration medium configuredto filter at least some of at least one blood component from separatedblood components passed to the filter via the flow path, and a filteroutlet for filtered blood components; a pump configured to pump at leastsome of the separated blood components from the chamber to the filtervia the flow path; and a pressure sensor configured to sense pressure ofblood components pumped to the filter, wherein the system is configuredto control the pump based on at least the pressure sensed by thepressure sensor.
 2. The system of claim 1, wherein the chamber comprisesa separation chamber, wherein blood components are centrifugallyseparated in the interior of the container, and wherein the systemfurther comprises a centrifuge rotor configured to be rotated about anaxis of rotation, the rotor comprising a portion configured to receivethe chamber.
 3. The system of claim 2, wherein the system is configuredso that the pump pumps blood components from the chamber during rotationof the centrifuge rotor.
 4. The system of claim 2, further comprising atleast one valving member on the centrifuge rotor, the valving memberbeing configured to control flow of at least some of the bloodcomponents during rotation of the rotor.
 5. The system of claim 2,further comprising at least one sealing member on the centrifuge rotor,the sealing member being configured to create a seal during rotation ofthe rotor.
 6. The system of claim 2, wherein the rotor further comprisesa portion configured to receive the filter, and wherein the system isconfigured so that the rotor rotates during filtering via the filterwherein the filter comprises a filter housing defining an interior spacecontaining the porous filtration medium, wherein the system isconfigured so that when the filter is received in the portion of therotor configured to receive the filter, the filter is positioned so thatblood components flow in the interior space in a direction facinggenerally toward the axis of rotation.
 7. The system of claim 1, whereinthe chamber comprises a bag formed of at least one of flexible andsemi-rigid material so that the interior of the chamber has a variablevolume.
 8. The system of claim 1, wherein the chamber is configured sothat the interior of the chamber has a variable volume.
 9. The system ofclaim 8, wherein the pump is configured to reduce the volume of thechamber interior.
 10. The system of claim 9, wherein the pump isconfigured to apply pressure to the chamber via hydraulic fluid.
 11. Thesystem of claim 10, wherein the sensor senses pressure of the hydraulicfluid.
 12. The system of claim 1, wherein the system is configured tocalculate a difference between pressures sensed by the pressure sensorin at least one time interval where blood components are pumped by thepump, determine when the calculated difference is at least apredetermined amount, and control the pump in response to at least thedetermination that the calculated difference is at least thepredetermined amount.
 13. The system of claim 1, further comprising anoptical sensor, wherein the system is configured to control the pumpbased on at least information sensed by the optical sensor and pressuresensed by the pressure sensor.
 14. The system of claim 13, wherein saidoptical sensor comprises a first optical sensor and a second opticalsensor, the first optical sensor being positioned to sense bloodcomponents in the chamber and the second optical sensor being positionedto sense blood components in a tubing line in flow communication withthe filter.
 15. A system for processing blood components, comprising: aseparation chamber comprising a chamber interior in which bloodcomponents are centrifugally separated, and an outlet port for passingat least some of the centrifugally separated blood components from thechamber interior; a flow path in flow communication with the outlet portof the separation chamber; a pump configured to pump at least some ofthe centrifugally separated blood components from the chamber andthrough the flow path; and a pressure sensor configured to sensepressure of blood components pumped by the pump; and a centrifuge rotorconfigured to be rotated about an axis of rotation, the rotor comprisinga portion configured to receive the separation chamber, wherein thesystem is configured to calculate a difference between pressures sensedby the pressure sensor in at least one time interval, determine when thecalculated difference is at least a predetermined amount, and controlthe pump in response to at least the determination that the calculateddifference is at least the predetermined amount.
 16. The system of claim15, wherein the system is configured so that the pump pumps bloodcomponents from the chamber during rotation of the centrifuge rotor. 17.The system of claim 15, further comprising at least one valving memberon the centrifuge rotor, the valving member being configured to controlflow of at least some of the blood components during rotation of therotor.
 18. The system of claim 15, further comprising a sealing memberon the centrifuge rotor, the sealing member being configured to create aseal during rotation of the rotor.
 19. The system of claim 15, furthercomprising a filter comprising a porous filtration membrane configuredto filter at least one blood component from the pumped blood products.20. The system of claim 15, wherein the chamber comprises a bag formedof at least one of flexible and semi-rigid material so that the interiorof the chamber has a variable volume.
 21. The system of claim 15,wherein the pump is configured to reduce the volume of the chamberinterior.
 22. The system of claim 21, wherein the pump is configured toapply pressure to the chamber via hydraulic fluid.
 23. The system ofclaim 22, wherein the sensor senses pressure of the hydraulic fluid. 24.The system of claim 15, further comprising an optical sensor, whereinthe system is configured to control the pump based on at leastinformation sensed by the optical sensor and pressure sensed by thepressure sensor.
 25. The system of claim 24, wherein said optical sensorcomprises a first optical sensor and a second optical sensor, the firstoptical sensor being positioned to sense blood components in the chamberand the second optical sensor being positioned to sense blood componentsin a tubing line associated with the flow path.